1. Field of the Invention
The present invention generally relates to a housing assembly having a bagging ring, and more specifically, a housing assembly for an air filter having a ring for bag-in/bag-out filter replacement.
2. Description of the Related Art
Contamination housing assemblies are used in critical processes where hazardous airborne materials must be prevented from escaping to the atmosphere. A filter is disposed in the contamination housing assembly to remove the hazardous and other materials from the air stream passing though the housing assembly. The housing assembly may be configured to include at least one filter, such as a particulate filter, such as a HEPA filter, and/or molecular filters for absorbing molecular contaminants.
The filters disposed in the contamination housing assembly are periodically replaced using a control barrier to protect change-out personnel from contaminants within the housing and from contaminants captured by the filters. The typical control barrier utilized is a plastic bag enclosure system such as described in U.S. Pat. No. 3,354,616, issued Nov. 28, 1967. The use of a plastic bag to remove and replace filters from a contamination housing assembly is typically known as a bag-in/bag-out procedure.
In a bag-in/bag-out filter change-out, a plastic bag is coupled to a bagging ring extending from the housing assembly and circumscribing an access port. The filter is drawn into the bag as it is removed from the housing. The bag is then sealed and cut between the filter and the housing, thus isolating the filter without exposing the interior of the contamination housing to the surrounding environment.
A second bag having a new filter disposed therein is secured to the bagging ring without removing the sealed bag. The sealed bag is then cut and/or removed to allow the new filter to pass into the housing while the second bag maintains a contamination barrier over the access port. The filter is sealing engaged to the housing. The access port is then sealed over the second bag and the contamination housing assembly is ready for operation.
Although conventional bagging rings utilized to attach filter change-out bags to contamination housings have robustly enabled contamination housings to be utilized in a variety of hazardous environments, the critical nature of the bag-to-housing seal, along with the increasing severity of the biomedical, radiological and carcinogenic contaminants present in these systems, improvements to the integrity of the bag-to-bagging ring seal is highly desirable.
Thus, there is a need for a housing having an improved bag to bagging ring seal.